title: Suitability of pharmacokinetic models for dynamic contrast-enhanced MRI of abdominal aortic aneurysm vessel wall: a comparison.
abstract: OBJECTIVE
  Increased microvascularization of the abdominal aortic aneurysm (AAA) vessel wall has been related to AAA progression and rupture. The aim of this study was to compare the suitability of three pharmacokinetic models to describe AAA vessel wall enhancement using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).
  
  
  METHODS
  Patients with AAA underwent DCE-MRI at 1.5 Tesla. The volume transfer constant (K(trans) ), which reflects microvascular flow, permeability and surface area, was calculated by fitting the blood and aneurysm vessel wall gadolinium concentration curves. The relative fit errors, parameter uncertainties and parameter reproducibilities for the Patlak, Tofts and Extended Tofts model were compared to find the most suitable model. Scan-rescan reproducibility was assessed using the interclass correlation coefficient and coefficient of variation (CV). Further, the relationship between K(trans) and AAA size was investigated.
  
  
  RESULTS
  DCE-MRI examinations from thirty-nine patients (mean age±SD: 72±6 years; M/F: 35/4) with an mean AAA maximal diameter of 49±6 mm could be included for pharmacokinetic analysis. Relative fit uncertainties for K(trans) based on the Patlak model (17%) were significantly lower compared to the Tofts (37%) and Extended Tofts model (42%) (p<0.001). K(trans) scan-rescan reproducibility for the Patlak model (ICC = 0.61 and CV = 22%) was comparable with the Tofts (ICC = 0.61, CV = 23%) and Extended Tofts model (ICC = 0.76, CV = 22%). K(trans) was positively correlated with maximal AAA diameter (Spearman's ρ = 0.38, p = 0.02) using the Patlak model.
  
  
  CONCLUSIONS
  Using the presented imaging protocol, the Patlak model is most suited to describe DCE-MRI data of the AAA vessel wall with good K(trans) scan-rescan reproducibility.
authors.affiliation: Department of Vascular Surgery, Maastricht University Medical Center, Maastricht, The Netherlands ; Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: V Lai
authors.initials: VL
authors.lastname: Nguyen
authors.forename: M Eline
authors.initials: ME
authors.lastname: Kooi
authors.forename: Walter H
authors.initials: WH
authors.lastname: Backes
authors.forename: Raf H M
authors.initials: RH
authors.lastname: van Hoof
authors.forename: Anne E C M
authors.initials: AE
authors.lastname: Saris
authors.forename: Mirthe C J
authors.initials: MC
authors.lastname: Wishaupt
authors.forename: Femke A M V I
authors.initials: FA
authors.lastname: Hellenthal
authors.forename: Rob J
authors.initials: RJ
authors.lastname: van der Geest
authors.forename: Alfons G H
authors.initials: AG
authors.lastname: Kessels
authors.forename: Geert Willem H
authors.initials: GW
authors.lastname: Schurink
authors.forename: Tim
authors.initials: T
authors.lastname: Leiner
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis* / Q000378:metabolism*; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008954:Models, Biological; D010599:Pharmacokinetics; D015203:Reproducibility of Results; D035501:Uncertainty
chemical_list: D003287:Contrast Media